The present invention relates to a resin-molded type photosensor such as photointerruptor or reflection-type photosensor.
As an example of resin-molded photosensors there is disclosed a reflection-type photosensor in U.S. Pat. No. 4,833,318 issued on May 23, 1989. In a conventional photosensor, the number of leads led out of a resin-molded package is a total of four, namely, two leads from a light-emitting part and other two leads from a light-receiving part. More specifically, two leads are respectively connected to an anode and a cathode of a light-emitting diode, as a light-emitting element, and when a phototransistor is used as a light-receiving element, two leads are connected to the collector and the emitter of the phototransistor, respectively. In particular, in a photointerruptor which is used for detecting the number of revolutions of a disk or the position of a moving plate, it frequently happens that the position of the disk or the moving plate and the position of the installed electronic component to which the detected signal is to be transmitted are separated by some distance for the reason of design requirement. In such a case, the conventional photointerruptor has four signal lines that need be laid, which becomes a factor for a price increase of the device due to the material cost for four copper wires, labor cost for their soldering, and the like.